| The widely used Line Commutated Converter(LCC)HVDC suffers from commutation failure which might cause severe economic and secure consequence.The recently proposed Modular Multilevel Converter(MMC)HVDC is expected to be an alternative solution.However,the half bridge MMC(HBMMC)cannot interrupt the short current caused by DC transmission line fault,which have stunted the engineering practice of MMC in the long-distance overhead transmission line situation.A hybrid LCC-FBMCC system was proposed in this paper.A hybrid LCC-MCC system was proposed in this paper,in which the LCC is adopted as rectifier while the full bridge MMC(FBMMC)is adopted as inverter.In order to put the innovative and theoretical system into use,some detailed and thorough research was made in this paper: Firstly,control stratagem especially start control system were put forward to make sure that the system can functioning smoothly.Secondly based on the parameter of a practical HVDC project,the electromagnetic simulation model of a ±500kV LCC-MMC hybrid HVDC transmission system was established in PSCAD/EMTDC.Then the fault ride ability and the impact of DC short fault on the power transmission was discussed,and compared with that of other HVDC system.Finally,the overvoltage of transmission line was compared with LCC-HVDC system which can present reference to the development and application of MMC in remote and bulk power transmission area. |
PDF Full Text Request